Method of producing seedless watermelon

ABSTRACT

The present invention is a novel method which improves the economical production of seedless watermelon fruit. The novel method involves using short vine pollinators in the production field to pollinate the triploid hybrids which result in increased yields.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a novel method of producingseedless watermelons using short vine pollinators. The present inventionalso relates to a watermelon seed, a watermelon plant, watermelonflower, and a watermelon variety which comprise having a short vine.

[0002] Watermelon belongs to the family Cucurbitaceae. Watermelon iscommercially grown from either seed or transplants. Citrullus is amember of the family Cucurbitaceae. The Cucurbitaceae is a family ofabout 90 genera and 700 to 760 species, mostly of the tropics. Thefamily includes pumpkins, squashes, gourds, melons, cucumber,watermelon, loofah, and several weeds. A bitter-fruited form ofCitrullus vulgaris appears to be the ancestor of the cultivatedwatermelon.

[0003] Successful watermelon production depends on attention to variouscultural practices. This involves soil management practices with specialattention to proper fertilization, crop establishment with appropriatespacing, weed control, the introduction of bees for pollination, andsuitable pollenizers for seedless watermelon, irrigation and pestmanagement. Watermelon fruit size and shape; rind color; thickness andtoughness; seed size, color and number; and flesh color, texture,soluble solids and freedom from fruit defects are all importantcharacteristics to be considered in selection of watermelon varieties.In addition, seedless watermelons should be free of hard seeds and haveundeveloped seeds that are small and innocuous.

[0004] Watermelon crops can be established in the field from seed orfrom transplants. Transplanting is becoming more common becausetransplanting usually results in earlier crops than those that aredirect seeded. Transplants are used extensively to establish seedlesswatermelon plantings. Diploid and triploid watermelon crops can beestablished easily with high quality transplants. Transplanting helpsachieve rapid, complete plant stands, especially where seed costs makedirect-seeding risky and expensive, as is the case with seedlesswatermelons. Most watermelon growers purchase plants from plant growingexperts who may arrange for transport to the field location.

[0005] For triploid seedless watermelon production, fruit set andenlargement is dependent upon growth regulators from the pollen grainsand from embryos in developing seeds within the fruit. Inadequatepollination results in triploid watermelon fruit that are triangular inshape and of poor quality. Inadequate pollination may increase theincidence of hollowheart. Triploid watermelon flowers do not producesufficient viable pollen to induce fruit set and development. Therefore,pollen from a normal diploid seeded watermelon variety must be provided.Planting the diploid pollenizer variety in the outside row of the fieldand then every third row is recommended. As an alternative, thepollenizer variety has been planted every third plant in each row butthis makes harvesting of the triploid fruit difficult because mixeddiploid and triploid fruit must be separated. This also makes plantingdifficult because blanks must be left where the diploid should go.Maintaining the rotation of three triploid to one diploid is not easilyaccomplished.

[0006] Currently, it is important to use a diploid pollenizer varietythat is marketable because between one-quarter to one-half of allwatermelons produced in the field will be of this variety. The rindpattern and/or shape of the seeded pollenizer fruit should bedistinguished easily from that of the triploid fruit to reduce confusionat harvest.

[0007] It is important that pollen from the diploid pollenizer varietyis available when female blossoms on the triploid plants are open andready for pollination. If planted too early, the diploid variety can setfruit and stop producing male blossoms while the triploid variety isstill producing many female blossoms. If planted too late, the triploidwill be ready to set fruit but not enough pollen will be ready toprovide fruit set.

[0008] Watermelon plants develop several vigorous and far-reachingvines, thus requiring large amounts of space for optimum growth andfruit development. Watermelons have been seeded with about two to aboutfour feet between plants in rows about six to about 15 feet apart. Thiswide spacing requires larger field sizes. Also, the wide spacingprovided less interplant competition for water. Cultural practices suchas irrigation and polyethylene mulch have led to the use of higher plantpopulations. Row spacing of 6-8 feet apart and plant spacing of 2-4 feetare common. Often, with close plant spacing, the individual plant setsfewer fruits, which still reach normal size.

[0009] Watermelon plants usually have separate male and female flowersbut sometimes produce perfect flowers. To achieve fruit set, pollen fromthe male flower must be transferred to a female flower on that plant oranother plant in the field. This pollen transfer is accomplished byseveral naturally occurring insects, but most effectively by thehoneybee. Poor or ineffective pollination of watermelons results inbottle-neck fruits of long-fruited watermelon varieties. Inround-fruited varieties, poorly pollinated fruits can be flat-sided ormisshapen.

[0010] Watermelon has small flowers. Flowering begins about 8 weeksafter seeding. Flowers of watermelon are staminate (male), perfect(hermaphroditic), or pistillate (female), usually borne in that order onthe plant as it grows. Monecious types are most common, but there areandromonoecious (staminate and perfect) types, mainly the oldervarieties or accessions collected from the wild. In many varieties, thepistillate or perfect flowers are borne at every seventh node, withstaminate flowers at the intervening nodes. The flower ratio of typicalwatermelon varieties is 7 staminate to 1 pistillate, but the ratioranges from 4:1 to 15:1.

[0011] Watermelon is the only economically important cucurbit withpinnatifid (lobed) leaves; all of the other species have whole(nonlobed) leaves. The leaves are pinnately divided into three or fourpairs of lobes, except for an entire-leaf (nonlobed) gene mutantcontrolled by the nl (nonlobed) gene. Watermelon growth habit is atrailing vine. The stems are thin, hairy, angular, grooved, and havebranched tendrils at each node. The stems are highly branched and up to30 feet long, although there are dwarf types (dw-1 and dw-2 genes) withshorter, less-branched stems. Roots are extensive but shallow, with ataproot and many lateral roots.

[0012] Vine length of watermelon varies from dwarf to long. For example,‘Charleston Gray’ and ‘Jubilee’, large-fruited varieties, have vines upto 30 feet long. Short or medium length vines are well suited tovarieties with small or medium sized fruit. For example, ‘Sugar Baby’,‘New Hampshire Midget’, and ‘Petite Sweet’ are short vined, having vinelengths of between about six to about 12 feet and ‘Crimson Sweet’ hasintermediate vine length.

[0013] Dwarf mutants have been discovered in watermelon. Two genes causedwarfing when they are in homozygous recessive condition: dw-1 and dw-2.‘Kengarden’ has the genotype dw-1 dw-2. Another gene mutant (JapaneseDwarf, dw-2 dw-2) has increased branching from the crown.

[0014] Fruit size is an important consideration in a breeding programsince there are different market requirements for particular groups ofshippers and consumers. The general categories are: icebox (<12 lb),small, sometimes called pee-wee (12-18 lb), medium (18-24 lb), large(24-32 lb), and giant (>32 lb). Fruit size is inherited in polygenicfashion, with an estimated 25 genes involved. Shippers in the UnitedStates work with particular weight categories, such as 18-24 lb forseeded and 14-18 lb for seedless.

[0015] In the production of triploid seedless hybrids, currently fromone-quarter to one-half of the field has to be planted to a diploidseeded variety. Therefore, higher yield of seedless watermelon per acrecould be obtained by using a more efficient pollenizer that would allowmore of the field to be planted to the triploid variety.

[0016] In theory, seedless triploid hybrids should provide higher yieldthan diploid hybrids because no energy is used in seed production.However, in practice this may not be the case. Fruit production intriploids is limited by the availability of viable pollen to inducefruit set. Pollination problems are responsible for improper fruitdevelopment. It is necessary for all three lobes of the stigma to befully pollinated if the fruit is to develop fully, and withoutcurvature. In the case of triploid hybrids, it is necessary to have upto one third of the field planted to a diploid pollenizer to assureadequate fruit development in the triploids which are male sterile.

[0017] Seedless triploid varieties are produced by crossing a tetraploid(2n=4x=44 chromosomes) inbred line as the female parent with a diploid(2n=2x=22) inbred line as the male parent of the hybrid. The reciprocalcross (diploid female parent) does not produce seeds. The resultinghybrid is a triploid (2n=3x=33). Triploid plants have three sets ofchromosomes, and three sets cannot be divided evenly during meiosis.This results in nonfunctional female and male gametes although theflowers appear normal. Since the triploid hybrid is female sterile, thefruit induced by pollination tend to be seedless. Unfortunately, thetriploid has no viable pollen, so it is necessary to plant a diploidvariety in the production field to provide the pollen that stimulatesfruit to form. Usually, one third of the plants in the field are diploidand two thirds are triploid, although production has been observed withas little as 20% diploids. Varieties should be chosen that could bedistinguished easily so the seeded diploid fruit can be separated fromthe seedless triploid fruit for harvesting and marketing.

[0018] Most of the tetraploid lines being used by the seed industry havegray rind so that, when crossed with a diploid line with striped rind,it will be easy to separate self-pollinated progeny (which will beseeded fruit from the female parent line) from cross-pollinated progeny(which will be seedless fruit from the triploid hybrid). The grower maydiscard the gray fruit so they are not marketed as seedless watermelonsby mistake. For example, if there is 4% of the fruit from the inbredparent then 4% of total fruits will be unmarketable and reducesmarketable yield.

[0019] The disclosed method increases the productivity and efficiency oftriploid seedless watermelons.

SUMMARY OF THE INVENTION

[0020] The present invention relates to a novel method of producingtriploid watermelon by using short vine pollinators which are eithertransplanted or seeded into the row. The present invention also relatesto a watermelon plant, and a watermelon variety which have short vines.Specifically, in one preferred embodiment the claimed invention involvesthe following steps:

[0021] 1) planting triploid plants and diploid short vine pollinatorplants in one or more rows;

[0022] 2) allowing said plants to mature and develop fruit; and

[0023] 3) harvesting said fruit.

DEFINITIONS

[0024] In the description and tables which follow, a number of terms areused. In order to provide a clear and consistent understanding of thespecification and claims, including the scope to be given such terms,the following definitions are provided:

[0025] Short vine. As used herein, “short vine” means a watermelon planthaving an average internode length of less than three inches and/or aplant diameter of less than six feet.

[0026] Average internode length. As used herein the term “averageinternode length” means the average length of the internodes of a plantgenotype measured in inches.

[0027] Lobed leaf. As used herein the term “lobed leaf” means a leafhaving two or more lobes.

[0028] Nonlobed leaf. As used herein the term “nonlobed leaf” means aleaf that is not lobed.

[0029] Yield. As used herein, the term “yield” means the total weight inpounds of all seedless watermelon fruit harvested per acre.

[0030] Plant. As used herein, the term “plant” includes plant cells,plant protoplasts, plant cells of tissue culture from which watermelonplants can be regenerated, plant calli, plant clumps and plant cellsthat are intact in plants or parts of plants such as pollen, flowers,seed, leaves, stems and the like.

[0031] Quantitative Trait Loci (QTL). As used herein, the term“quantitative trait loci (QTL)” refer to genetic loci that control tosome degree numerically representable traits that are usuallycontinuously distributed.

[0032] Regeneration. Regeneration refers to the development of a plantfrom tissue culture.

[0033] Plant diameter. As used herein, the term “plant diameter” meansthe average length of a plant measured in inches.

[0034] Single Gene Converted. Single gene converted or conversion plantrefers to plants which are developed by a plant breeding techniquecalled backcrossing wherein essentially all of the desired morphologicaland physiological characteristics of an inbred are recovered in additionto the single gene transferred into the inbred via the backcrossingtechnique or via genetic engineering.

[0035] Vine length. As used herein, the term “vine length” is the lengthof the runners (vines) and is measured in inches.

[0036] Short vine diploid pollinator. As used herein, the term “shortvine diploid pollinator” means a diploid variety that has a plantdiameter of less than six feet and/or an average internode length ofless than 3 inches.

[0037] Average length of longest runner. As used herein, the term“average length of longest runner” means the average length of thelongest runner of the watermelon plant in inches.

[0038] Triploid plants. As used herein, “triploid plants” means plantsor transplants derived from planting triploid seeds or frommicropropagation.

[0039] Diploid plants. As used herein, “diploid plants” means plants ortransplants derived from planting diploid seeds or frommicropropagation.

DETAILED DESCRIPTION OF THE INVENTION

[0040] The present invention relates to a novel method of producingtriploid watermelon which involves the use of short vine diploidpollinators. The present invention also relates to a watermelon plant, awatermelon variety and a watermelon hybrid which has the short vinecharacteristics.

[0041] The present invention is a novel method which uses a diploidpollinator that takes less space in the field and reduces the totalusage of water and fertilizer by diploid plants in a field. This novelmethod allows the triploid hybrid to produce higher yields due in partto having more space, water, sunlight and nutrients available for thetriploid plants and also due to having additional triploid plants perfield. The use of this novel short vine diploid pollinator also allowseasier harvesting of the triploid fruits produced, since the diploidfruits remain in, or adjacent to, the row where planted and aretherefore not in the way and allow easier manual or mechanicalharvesting.

[0042] Use of a short vine pollinator allows the grower to manage thewater, fertilizer and field regimes totally based on the needs of thetriploid plants and not managed based on the diploid plants in thefield.

[0043] In one embodiment of the present invention, transplants of thediploid short vine pollinator seed and transplants of the triploid seedare planted in each row. In a preferred embodiment, a higher number oftriploid transplants are planted per field than conventional methods.For example, at a specific field and location, currently the growerplants a total of 2,000 transplants per acre and the field contains bothdiploid (around 25%-33%) and triploid genotypes (around 67%-75%). In onepreferred method of the present invention, the grower establishesapproximately 2,000 plants of the triploid and then plants about 400 toabout 1,200 plants of the short vine diploid. The short vine diploidplant of the present invention is small and therefore does not requireadditional space in the row. In comparison, with current productionmethods, the grower is planting on the average approximately 1,333triploid transplants and 667 diploid transplants per acre. Whereas, withthe method of the present invention, 2,000 triploid plants and about400-1,200 diploid plants are planted, resulting in an increase of 33% to50% more triploid plants per acre. These additional triploid plantsproduce a significant increase in total triploid fruit yield per acre.

[0044] In another embodiment of the present invention, the diploid shortvine pollinator seed is mixed with the triploid seed prior to planting.In a preferred embodiment, a higher number of triploid seeds are plantedper field. For example, at a specific field and location, if the growerplants a total of 2,000 seeds per acre the field will contain bothdiploid (around 25%-33%) and triploid genotypes (around 67%-75%). In onepreferred method of the present invention, the grower would plant 2,000seeds of the triploid and in addition 200 seeds of the short vinediploid. The short vine diploid plant of the present invention is smalland does not require additional space in the row. Therefore in thisexample, with current methods the grower is planting approximately 1,333triploid seeds and 667 diploid seeds per acre. Advantageously, with themethod of the present invention, 2,000 triploid seeds and 200 diploidseeds are planted, resulting in 66^ A more triploid plants per acre,which produces a significant increase in yield per acre.

[0045] The established plants in a field can be developed from thefollowing methods: 1) planting seeds or any portions of seed; 2) primedor coated seed, or any portions of the seed; 3) plants, or portionsthereof, derived from tissue culture or cell culture; 4) cuttings; and5) planting transplants into the field.

[0046] The triploid and diploid seeds can be mixed prior to planting andthen sowed or the triploid seed can first be planted, followed byplanting the diploid seed or vice versa, depending on expectedpollination dates.

[0047] The method of the present invention had the unexpected result ofproviding a good pollen source without having the disadvantages oflonger vined diploid pollinators varieties.

[0048] The present invention also completely eliminates the need for thecurrent planting procedure of having one row of diploid plantsalternated with every two rows of triploid plants.

[0049] Other advantages of the present invention include the diploidpollinator is easy to see and avoid stepping on when harvesting. Thediploid pollinator is close to the row and therefore should be easy toavoid when picking triploid fruits.

EXAMPLES

[0050] The present invention is further detailed in the followingExamples, which are offered by way of illustration and are not intendedto limit the invention in any manner. Standard techniques well known inthe art or the techniques specifically described are utilized.

Example 1 Short Vine Diploid Pollinators

[0051] Sixty-nine diploid lines of the short vine plant habit type havebeen developed. Sixteen lines are shown in Table 1. Of these 16 lines inTable 1, there are 4 different rind pattern types including gray, darkgreen, light green with narrow stripes, and light green with widestripes. Also included are lines having: 1) both red and yellow fleshedlines; 2) round, blocky and elongated fruit shapes and 3) lobed andnonlobed leaf types.

[0052] These diploid short vine lines can be crossed with many othergenetic backgrounds to select for additional short vine lines. TABLE 1Short Vine Pollinator Number/ Lobed or ID Rind Pattern Flesh Color FruitShape Non-lobed 6753 Gray Red Round Lobed 6741 Gray Red Round Non-lobed4935 Gray Red Blocky Non-lobed 4963 Gray Red Elongated Lobed 4923 DarkGreen Red Round Lobed 4922 Dark Green Red Round Non-lobed 4959 Dk.mottled stripe Red Round Lobed 4915 Dk. mottled stripe Red RoundNon-lobed 4961 Dk. mottled stripe Red Blocky Lobed 4962 Dk. mottledstripe Red Blocky Non-lobed 4956 Dk. mottled stripe Red Long Lobed 4957Dk. mottled stripe Red Long Non-lobed 4905 Tiger stripe Red RoundNon-lobed 4932 Tiger stripe Red Blocky Lobed 4941 Tiger stripe Red RoundLobed 4937 Gray Yellow Round Non-lobed

Example 2

[0053] Short vine diploid lines 6741 and 6754 have been tested aspollinators of triploid plants under field conditions. During 2001, atfive different locations in Florida, Georgia and South Carolina,plantings were made using either alternate rows for the pollinator orwith the pollinator planted in the same row as the triploid plants. Theshort vine diploid pollinator induced triploid fruit set earlier,approximately 10 days earlier, when planted in the same row as comparedto planting the diploid plants in separate alternate rows from thetriploid plants. The quantity of fruit set by the triploid plants wasnormal and similar in number and size to the standard long vinepollinator. Line 6741 produced more triploid fruit which set earlierthan the 6754 line.

Example 3

[0054] In 2001, a location near Gilroy, Calif. was planted and harvestedwhere the short vine pollinator was planted at different intervalsbetween the triploid plants down the same row including at the intervalsof (every 2, 3, 4, 5 triploid plants). Fruit set decreased at a spacingof one pollinator every 4 or 5 plants but fruit set was normal usingshort vine pollinators for every 2 or 3 triploid plants compared to longvine pollinators.

Example 4 Line 6741

[0055] The watermelon diploid line 6741 of the present invention havethe characteristics of a short vine and results in a significantincrease in triploid fruit production when used as a short vinepollinator for triploid hybrid production. Using 6741 as a pollinatorprovides a great benefit because it results in easier harvest andreduced occurrence of undesirable diploid fruit, which when harvestedmust be kept separate from the seedless triploid watermelon.Additionally, the use of 6741 as pollinator results in the yield of thetriploid watermelon of the present invention is increased substantially.

[0056] In the development of line 6741, ‘Sugar Bush’ was crossed with‘Mickylee’ in 1986 and selfed for 4 generations. A selection was thencrossed with line ‘B25’ in 1991 and selected for non-lobed, short vineand light green rind with no stripes.

[0057] Trait characteristics of watermelon line 6741 are listed below:

[0058] MATURITY: 80 days (a little earlier than main season/avg)

[0059] FRUIT: Rind is light green with faint mottling and no stripes;flesh is red

[0060] SIZE:

[0061] Diameter—8 inches

[0062] Length—9 inches

[0063] Rind—⅝ inch

Example 5 Line 6754

[0064] The watermelon diploid line 6754 of the present invention havethe characteristics of a short vine and results in a significantincrease in fruit production when used as a short vine pollinator fortriploid hybrid production. Using 6754 as a pollinator provides a greatbenefit because it results in easier harvest and reduced occurrence ofundesirable diploid fruit which when harvested must be kept separatefrom the seedless triploid watermelon. Additionally, the use of 6754 asa pollinator results in the yield of the triploid watermelon of thepresent invention is increased substantially.

[0065] Trait characteristics of watermelon line 6754 are listed below:

[0066] MATURITY: 80 days

[0067] FRUIT: Rind—Light green with faint mottling and no stripes;flesh—red

[0068] SIZE:

[0069] Diameter—8 inches

[0070] Length—9 inches

[0071] Rind—⅝ inch

[0072] This invention is also directed to methods for producing aseedless triploid watermelon fruit by using short vine diploidpollinators.

[0073] As used herein, the term “plant” includes plant cells, plantprotoplasts, plant cell of tissue culture from which watermelon plantscan be regenerated, plant calli, plant clumps, and plant cells that areintact in plants or parts of plants, such as pollen, flowers, leaves,rind, flesh and the like.

[0074] When the term inbred watermelon plant is used in the context ofthe present invention, this also includes any single gene conversions ofthat inbred. The term single gene converted plant as used herein refersto those watermelon plants which are developed by a plant breedingtechnique called backcrossing wherein essentially all of the desiredmorphological and physiological characteristics of an inbred arerecovered in addition to the single gene transferred into the inbred viathe backcrossing technique. Backcrossing methods can be used with thepresent invention to improve or introduce a characteristic into theinbred. The term backcrossing as used herein refers to the repeatedcrossing of a hybrid progeny back to one of the parental watermelonplants for that inbred. The parental watermelon plant which contributesthe gene for the desired characteristic is termed the nonrecurrent ordonor parent. This terminology refers to the fact that the nonrecurrentparent is used one time in the backcross protocol and therefore does notrecur. In a typical backcross protocol, the original inbred of interest(recurrent parent) is crossed to a second inbred (nonrecurrent parent)that carries the single gene of interest to be transferred. Theresulting progeny from this cross are then crossed again to therecurrent parent and the process is repeated until a watermelon plant isobtained wherein essentially all of the desired morphological andphysiological characteristics of the recurrent parent are recovered inthe converted plant, in addition to the single transferred gene from thenonrecurrent parent.

[0075] The selection of a suitable recurrent parent is an important stepfor a successful backcrossing procedure. The goal of a backcrossprotocol is to alter or substitute a single trait or characteristic inthe original inbred. To accomplish this, a single gene of the recurrentinbred is modified or substituted with the desired gene from thenonrecurrent parent, while retaining essentially all of the rest of thedesired genetic, and therefore the desired physiological andmorphological, constitution of the original inbred. The choice of theparticular nonrecurrent parent will depend on the purpose of thebackcross, one of the major purposes is to add some commerciallydesirable, agronomically important trait to the plant. The exactbackcrossing protocol will depend on the characteristic or trait beingaltered to determine an appropriate testing protocol. Althoughbackcrossing methods are simplified when the characteristic beingtransferred is a dominant allele, a recessive allele may also betransferred. In this instance it may be necessary to introduce a test ofthe progeny to determine if the desired characteristic has beensuccessfully transferred.

[0076] Many single gene traits have been identified that are notregularly selected for in the development of a new inbred but that canbe improved by backcrossing techniques. Single gene traits may or maynot be transgenic, examples of these traits include but are not limitedto, male sterility, herbicide resistance, resistance for bacterial,fungal, or viral disease, insect resistance, male fertility, enhancednutritional quality, industrial usage, yield stability and yieldenhancement. These genes are generally inherited through the nucleus.Some known exceptions to this are the genes for male sterility, some ofwhich are inherited cytoplasmically, but still act as single genetraits. Several of these single gene traits are described in U.S. Pat.Nos. 5,777,196; 5,948,957 and 5,969,212, the disclosures of which arespecifically hereby incorporated by reference.

[0077] A further aspect of the invention relates to tissue culture ofwatermelon plants designated N3C13. As used herein, the term “tissueculture” indicates a composition comprising isolated cells of the sameor a different type or a collection of such cells organized into partsof a plant. Exemplary types of tissue cultures are protoplasts, calli,plant clumps, and plant cells that can generate tissue culture that areintact in plants or parts of plants, such as embryos, pollen, flowers,leaves, roots, root tips, anthers, and the like. In a preferredembodiment, tissue culture is embryos, protoplast, meristematic cells,pollen, leaves or anthers. Means for preparing and maintaining planttissue culture are well known in the art. By way of example, a tissueculture comprising organs such as anthers, has been used to produceregenerated plants. (See U.S. Pat. Nos. 5,445,961; 5,322,789; 5,948,957and 5,969,212, the disclosures of which are incorporated herein byreference).

Deposit Statement

[0078] Watermelon seeds of 6741 have been placed on deposit with theAmerican Type Culture Collection (ATCC), Manassas, Va., under DepositAccession Number ______ on Dec. 21, 2001.

[0079] Although the foregoing invention has been described in somedetail by way of illustration and example for purposes of clarity andunderstanding. However, it will be obvious that certain changes andmodifications such as single gene modifications and mutations,somoclonal variants, variant individuals selected from large populationsof the plants of the instant inbred and the like may be practiced withinthe scope of the invention, as limited only by the scope of the appendedclaims.

What is claimed is:
 1. A method of producing triploid watermelon fruitcomprising: a) planting triploid plants and diploid short vinepollinator plants in one or more rows; b) allowing said plants to matureand develop fruit; and c) harvesting said fruit.
 2. Watermelon fruitproduced by the method of claim
 1. 3. The method of claim 1, whereinsaid diploid short vine pollinator plant is planted in a ratio ofdiploid to triploid plants of between about 1:1 to about 1:10.
 4. Themethod of claim 3, wherein said diploid plant is planted in a ratio ofabout one diploid plant to about two triploid plants.
 5. The method ofclaim 3, wherein said diploid plant is planted in a ratio of about onediploid plant to about three triploid plants.
 6. The method of claim 1,wherein said diploid and triploid plants are planted in the same row inthe field.
 7. The method of claim 1, wherein said diploid plants areplanted in separate rows from said triploid plants.
 8. A diploid shortvine pollinator line designated 6741, a sample of said seed having beendeposited under ATCC Accession No. ______.
 9. A watermelon plant, orparts thereof, produced by growing the seed of claim
 8. 10. Pollen ofthe plant of claim
 9. 11. An ovule of the plant of claim
 9. 12. A tissueculture of regenerable cells of a watermelon plant of line 6741, whereinthe tissue regenerates plants capable of expressing essentially all themorphological and physiological characteristics of the line
 6741. 13. Atissue culture according to claim 12, the cells or protoplasts beingfrom a tissue selected from the group consisting of leaves, pollen,embryos, roots, flowers, and rind.
 14. A watermelon plant regeneratedfrom the tissue culture of claim 12, capable of expressing all themorphological and physiological characteristics of line
 6741. 15. Amethod for producing a hybrid watermelon seed comprising crossing afirst parent watermelon plant with a second parent watermelon plant andharvesting the resultant hybrid watermelon seed, wherein said first orsecond parent watermelon plant is the watermelon plant of claim
 9. 16. Ahybrid watermelon seed produced by the method of claim
 15. 17. A hybridwatermelon plant, or parts thereof, produced by growing said hybridwatermelon seed of claim
 16. 18. Watermelon seed produced by growingsaid hybrid watermelon plant of claim
 17. 19. The watermelon plant, orparts thereof, of claim 9, wherein the plant or parts thereof have beentransformed so that its genetic material contains one or more transgenesoperably linked to one or more regulatory elements.
 20. A method fordeveloping a watermelon plant in a watermelon plant breeding programusing plant breeding techniques which include employing a watermelonplant, or its parts, as a source of plant breeding material comprising:using the watermelon plant, or its parts, of claim 9 as a source of saidbreeding material and wherein plant breeding techniques are selectedfrom the group consisting of: recurrent selection, backcrossing,pedigree breeding, mass selection, restriction fragment lengthpolymorphism enhanced selection, genetic marker enhanced selection, andtransformation.
 21. A watermelon plant, or parts thereof, produced bythe method of claim
 20. 22. The watermelon plant of claim 9, furthercomprising a single gene conversion.
 23. The single gene conversionwatermelon plant of claim 22, wherein the gene confers a characteristicselected from the group consisting of: herbicide resistance, insectresistance, and resistance to bacterial, fungal, or viral disease.